Sunday, June 17, 2007

Dawn redwood (Metasequoia glyptostroboides)

Those who think of New Jersey as home to such phenomena as the Sopranos, suburban sprawl, and pay-to-play politics should know this: the Garden State is also home to the best collection of dawn redwoods in the country. Matthew Belsky of Skidmore College, who keeps track of such things(1), finds six of the country's ten biggest, best, and oldest dawn redwoods within the borders of New Jersey. (You might not find one on the grounds of the Bada Bing! Club --- four of the best trees are in Princeton --- but dawn redwoods can be found if you look.) We have a few dawn redwoods in Plainfield. The most easily visible dawn redwood I know of in town is at 527 Belvidere Avenue between Seventh Street and South Avenue.

City Councilman Cory Storch made me aware of a dawn redwood that I had previously missed at 701 Belvidere Avenue. The tree is next to the driveway on Ravine Road.

A former owner of 1165 Hillside Avenue tells me that the dawn redwood in the backyard (visible over the roof of the house) was planted in the mid-1960s.

Dawn redwoods and bald cypresses both lose their needles in winter. The two species are distinguishable from one another by a few easily recognizable features. Dawn redwoods have "armpits" beneath their large branches, giving the trunk a heavily buttressed appearance. For the most part, dawn redwood twigs appear opposite each other roughly parallel to the ground; bald cypress twigs are arrayed in a spiral around the branch as seen in the end-on photograph below.

Also, dawn redwoods have larger leaves. The foliage is shown at about 1.3 times the actual size.

The photograph shows that the dawn redwood's leaves are opposite each other. If you hold a bald cypress twig almost up to your nose, you can see that its leaves are alternate, not opposite.

Bald cypresses are hard to find around here. Ambleside Gardens on Route 206 in Hillsborough has one that was planted in 1966 just inside the entrance to the nursery. There is another at 6 Calvert Avenue East in Edison, just off Grove Avenue.

Dawn redwood buttressing is well seen in a tree planted in 1949 at Princeton's Marquand Park. The size-reference dog in the photograph weighs 52 lbs.

As the photograph shows, the base of a mature dawn redwood spreads to become quite massive. This feature limits the usefulness of the species as a street tree. Maplewood, however, has used them as street trees since the 1950s and is rather well-known for its dawn redwoods. In my experience, young dawn redwoods are not at all tolerant of drought, another serious limitation for street tree use.

Dawn redwood was first discovered as a fossil in 1941 by a Japanese scientist working in occupied China during World War II. He assumed that the tree had been extinct for millions of years and created the first genus for an extinct plant, Metasequoia. In the same year, a Chinese scientist who had fled to China's remote interior to escape the Japanese invasion discovered a living example of an unfamiliar tree, identified five years later as the same species as the fossil dawn redwood. Seeds were sent to Harvard's Arnold Arboretum and distributed from there around the U.S. in 1948. The growth of dawn redwoods is legendarily fast. The tallest dawn redwood in this country is 140 feet tall, but the tree is not yet 70 years old.